Few data on speeds on the net.
For your information I measured on my computer in for a big USB2 1GB single file:
Writing 4.6 MB / sec and Playback 21.5 MB / sec (in reference with my Corsair Flash traveling GT: Writing 17.6 MB / sec, Reading 34MB / sec for the same file)
But hey, you might expect given the size of the beast.
A good product anyway.